Iwao Sato

Studies on bone resorption by human monocytes.

ヒト単球の骨吸収機序への関与を明らかにしたいために, ヒト末梢血から分離した単球を用い, in vitro での骨吸収能を, ラットの頭蓋冠あるいは合成ハイドロキシアパタイト (HA) を用いて検討した。他方, ヒト末梢リンパ球に phytohemagglutinin (PHA) を添加し, 48時間培養して得た上清 (Osteoclast activating factor: OAF, を含む) を用い, 単球の骨吸収能, 3H-Thymidine の取り込み, それにNBT還元能に及ぼす影響などについて検討した。結果は, ヒト単球が骨の吸収に関与する実態とその吸収作用がOAFによって増強される可能性を示唆することができた。

ラット歯槽骨培養上清 (Bone-sup) のラット腹腔マクロファージ走化活性におよぼす影響

tion. Esterase activity and viability of the induced cells was more than 85% and 98% respectively. Rat alveolar bone supernatant (Bone-sup) was prepared by taking out the alveolar bone and incubating it in RPMI 1640 medium at 37•Ž, in 5% CO2 in air. During incubation, the stimulants parathyroid hormone ( PTH) or sonicated Bacteroides gingivalis 381 (BG) , or no stimulant were added. The effect of Bone-sup on chemotactic activity of macrophages was determined by the membrane filter method of bioassay in a multi-well chamber. In all experiments, N-formyl-Lmethionyl-L-leucyl-L-phenylalanine was used as a positive control. Chemotactic activity of macrophages was enhanced by Bone-sup with or without a stimulant. The peak of chemotactic activity was reached in 96 hr of incubation. Factors from rat alveolar bone or fragments of bone accelerated the chemotactic activity of macrophages, suggesting that the factor affects the function of macrophages.

Effects of Culture Supernatants of Leukocytes from Periodontal Patients on Monocyte-Mediated Hydroxyapatite Resorption

In this study, the effects of culture supernatants on various activities of the monocyte, as a bone-resorbing cell, were compared between peripheral blood leukocyte (PBL) cultures from patients with periodontal disease and those from subjects with a clinically healthy periodontium. We have reported that normal human monocytes in vitro induce the release of calcium from synthetic hydroxyapatite particles and that the activity is enhanced by supernatants from cultures of stimulated or non-stimulated peripheral blood leukocytes. Monocytes from both patients and healthy subjects induced the release of calcium from hydroxyapatite particles (HA) to an equal degree. This activity of monocytes from healthy subjects showed a statistically significant increase by addition of supernatants from stimulated or unstimulated cultures of peripheral blood leukocytes from periodontitis patients. This increase was greater than that seen with supernatants from cells of healthy controls. The Nitro Blue Tetrazolium reduction activity and [3H]-thymidine incorporation of monocytes were also increased by addition of the supernatants from leukocyte cultures from either patients or healthy controls, but no significant difference was noted in the increase. These results suggest that the HA-resorbing activity of monocytes was enhanced by factors from cultured leukocytes. Furthermore, these studies showed that production of these factors by peripheral mononuclear cells from patients with periodontal disease was greater than that seen with cells from normal subjects.

[Effect of culture supernatants of peripheral blood leukocytes on the bone-mineral resorbing activity of human monocytes].

骨吸収に, 単球が関与している報告は少なくないが, その詳細な機序については, 明らかではない。さきに著者らは, 合成ハイドロキシアパタイト (HA) を用いた in vitro で骨吸収試験 (合成HAからのカルシウム解離活性) を行ない, 単球のもつ骨吸収能の一端を明らかにしている。ここでは, 歯垢 (Dental plaque: DP) あるいは Phytohemagglutinin (PHA) によって刺激した歯周疾患々者の末梢血白血球の培養上清が, 合成HAからのカルシウム解離活性を著明に亢進させたことから, 単球の骨吸収能にリンホカイン (特に, 破骨細胞活性化因子, Osteoclast activating Factor: OAF) の関与のあることを示唆した。